Earth tamping device



ug. 15, 1939. J, A, .MCDOUGALL ET AL 2,169,468

' EARTH TAMPING DEVICE Filed Oct. l5, 1958 5 Sheets-Sheet 1 n in l u I n ELm Attorneys Aug. l5, 1939. J. A- MCDOUGALL ET AL EARTH TAMPING DEvIE s sheets-sheet 2 Filed Oct. l5, 1958 gall Bober E MG Gary mw. hv

Jv. A. MCDOUGALL ET A1. 2,169,468

Aug. 15, 1939.

EARTH TAMPING DEVICE Filed Oct. l5, 1958 3 Sheets-Sheet 3 'III Inl/enfers 'JO/2n A?. McDougal? Baberz E Mcdry T Attorneys Parenfei Aug. 1,5, 1939 UNITED STATES EARTH TAMPING DEVICE John A. McDougall and Robert E. McGary,

Portland, Oreg.

Application October 15, 1938, SerialNo. 235,265

'7 Claims.

This invention relates to means for tamping hammer and earth tamping shoe, these elements earth on sloping embankments, inclined walls` and bottoms of canals, excavations, etc., on which concrete surfacing ,is to be placed. In such work it generally becomes necessaryto tamp the earth thoroughly first before the concrete surfacing is applied. i

, While various tamping means, which are more or less practical, have been devised for horizontal surfaces, these means are not eicient for use on sloping surfaces, such as those above mentioned. Consequently, it has been necessary, as well as customary, lup to the present time, when preparing the surface of canals, reservoirs, earth l5 filled dams and dykes, and similar excavations? and other embankments for concrete lining, to have the tamping performed by manual labor. This procedure is slow and expensive as well as ineiiicient. h

The object of this invention is to provide a machine-operated tamping device which is especially adapted for use on sloping surfaces of excavations and embankments, by means of which the desired tamping of such surfaces can be done more efficiently and economically.

A further object of this invention is to provide a tamping device of this nature suitable for sloping embankments, and thel like, which will be simple in construction, easy to operate, and which can be set up without difficulty and readily moved from place to place as the work progresses.

These and other objects we attain by providing a movable carriage on which is mounted a powerdriven hammer, a rigid supporting structure supporting tracks for the carriage and adapted to hold the carriage always spaced a proper distance from the surface to be tamped, power means carried on the supporting structure for moving the carriage thus transversely across suro faces to be tamped while at the same time operating the power-driven hammer, a tamping shoe actuated by the hammer and contacting the surface to be tamped, and other parts, all of which will be apparent from the following brief de- 45 scription with reference to the accompanying drawings. In the drawings: Fig. 1 is an assembly view showing an embodiment of our invention in operation in a canal 50 excavation;

Fig. 2 is an enlarged sectional elevation taken `on the plane of line 2--2 in Fig. 1;

Fig. 3 is a vertical section taken on the plane of line 3-3 of Fig. 2; u Fig. 4 is a side elevation of the compressed air being detached and enlarged from the assembly Fig. 1 for purposes of clarity;

Fig. 5 is a detail plan view ofthe tamping shoe; Fig. 6 is a. vertical transverse section corresponding to the line 6 6 of Fig. 5 but drawn to a larger scale; and y Fig. 7 is an assembly view illustrating a modified form of our invention in operation on an earth embankment such as the face of a reservoir, dyke, or the like.

Referring first to Fig. 1, the entire apparatus for tamping the inclined sides and the bottom of a canal or other excavation is carried on a rigid frame made to conform in general shape to the transverse contour of the excavation and adapted to travel on rails C laid on the-berm grade or terrace of the canal. This frame consists of a. pair of inverted trusses A rmly secured together in spaced parallel relationship by suit- /able connecting members (not shown) and mounted on two pairs of double-flanged Wheels B, each pair being arranged in tandem, and each pair rolling on the rail C accurately laid at each side of the top of the sides of the canal to coincide with the finished grade. A set of guides consisting of two pairs of channel members is disposed between and firmly secured to the trusses A in parallelism with the sides and bottom of the excavation, each pair of guides comprising a lower channel D and an inverted upper channel E (see also Figs. 2 and 3). These four channel members serve to guide'the movement of a carriage F in its travel transversely of the ditch and at a uniform distance from the sides and bottom thereof. y

The carriage F comprises two substantial axles Ill and II (Fig. 3), carried on two pairs of rubber-tired wheels I2 and I3 adapted to roll in the channel guides D and E; a'rigid guide frame I4 supported in a central position between the said wheels and held perpendicuar to the axles IIJ and II by suitable bracing members I4f secured to the axles; and a chassis I5 flrmly attached to the braces Il.

A compressed air hammer I6, similar to the type in conventional use for driving piles is reciprocally disposed in the guide frame I4. This air hammer has a double-acting ram I1 (see Fig. 3) which is caused to reciprocate in a" ported cylinder formed in the body of the hammer by compressed air brought to the hammer by a exible hose I8 and introduced therein via the usual valve chest I9. The hammer I6 may s I44 orraised andlowered therein by compressed A upon variance`of pressure in the top of saidcylinder 2|, and -havifig an upstanding piston rod 2l which is connected by a wire rope 24 to the top head of the hammer Il, said wire rope being passed over a sheave 2l superimposed on the guide frame I4.

In operation, the ram I1 delivers rapid blows on a tamping shoe 26 of special design. This shoe, as illustrated in detail in Figs. 5 and 6, is preferably rectangular in plan and has the edges which are parallel to the carriage axles Il and Il bent upwardly as shown. A concentric boss 21 is made integral with, orffirmly secured to, the shoe 26 and is additionally supported by pairs of longitudinal ribs 2l and transverse ribs 2l, the whole being a very rigid structure capable of transmitting, without fracture or bending, the impact of the ram l1 te the earth beneath the shoe and thus compacting it. However, we have found it practical to insert a concussion plug 26 made'of wood, soft metal or the like in a tapered hole in the boss 21, the top of the plug 3l being of the same diameter as the ram I1 and extending slightly above the top of the boss`21. A binding band 3| prevents this extending end ofthe plug from spreading under the blows of the ram. The conclusion plug 36 may be readily removed from thel shoe 26 when necessary by inserting a suitable punch in a hole I2 provided in th bottom of the shoe. The size, shape and proportions of the tamping shoe 26 may be varied to suit different earth conditions and to give the required number ofpounds per square foot pressure proportional to the force exerted by the hammer ram.

The tamping shoe 26 is normally held against the bottom of the hammer I6 by a pair of substantial compression springs 22 which bear at the lower end on a rigid plate 24 firmly secured to the base of the hammer I6 and at the upper end on shouldered sleeves 25 reciprocally disposed in rigid brackets I6' attached to the hamm'er body. The sleeves 36 are detachably mounted on the threaded upper ends of tie rods 36 which pass down through the springs 23 and plate 24 and are removably kattached to the ribs 26 of the shoe by bolts Il, as seen in Fig. 4.

Thus, on the downward stroke of the ram I1, the tie rods 36 are drawn downwardly andthe shouldered sleeves 36. vsliding in the nxed brackets I6', compress the springs 32. As the ram recedes, the shoe is of course immediately retracted by the extension of the springs 22. Since these tie rods 36 constitute the sole supporting means for the tamping shoe 26, it is necessary to provide means for returning the'shoe to the proper position each time relative to the ram I1 so that no twisting force is exerted on the shoe by the subsequent blows of the ral'n. This we accomplish by tapering the upper'portion of the shoe boss 21 to correspond with beveled' y and cylinder 2| may be connected to any sultable apparatus for furnishing compressed air or steam, and the entire carriage F may bemoved back and forth in the guides D and E by any .suitable prime mover, but we prefer to carry all devices.

' the hammer I6 thus actuating the ram I1 and the necessary 'y power 'l furnishing means on the traveling frame composed of the trusses A and thus provide a self-contained machine. Therefore we providea tank T to which air under pressure is delivered by a conventional engineg driven compressor G, the 'tank Tserving to store the compressed air for thel hammer I6, cylinder 2|, and also for the carriage moving hoist H and frame moving winch J (see Fig. 1). The carriage moving hoist H is of the dual drum type in which one drum can be madev to paylout its line as the other line is wound in. The line 29 runs from one drum around a sheave 4l carried on a suitable braced post at one end of the truss frame to a sheave 4I mounted at the-rear end 1| oi' the carriagechassis I5 back to another sheave 42 on the trusspost and thence to anchorage on the axle I I of the carriage F (Fig. 3). In similar manner, the other line passes around sheaves 44, 46 and 46 to the carriage axle 10 an additional sheave 41 carrying the line 43 clear of other moving parts. Thus when air under pressure is supplied in the usual manner from the main air pipe K connected to the tank T to the drums of the hoist H, the carriage F may be moved in the guides D and E and caused to ascender descend the inclined sides of the canal excavation. y

In order to keep the flexible hoses I8 and 20 out of the path of the moving carriage F, we provide means for maintaining these hoses reasonably taut. Each of the iiexible hoses is clamped as at 4I and'49 in Fig. 2 to the top of the hammer 'guide frame I4 and extends from there between pairs of grooved Wheels 50 mounted on cross nembers of the trusses and over similar grooved wheels 5I carriedona suitable super-structure to connections with the main air pipe K, the, counter-weighted sheaves 52 and 53 taking upthe slack in the hoses I6 and 20, respectively.

'I'he winch J (Fig. l) for moving the entire apparatus along the excavation receives compressedair via the branch pipe L and has two drums which wind in tow lines 6I) and 6I which pass around sheaves 62 and 63. These hoist drums are rotated at the same speed when it is -desired to draw the traveling frame straight In compacting the earth 'on the inclined sides and bottom of a canal or other excavation, the apparatus is operated as. follows: The carriage F, with the shoe 26 and hammer I6 raised clear of ground by air introduced in cylinder 2|, is brought to the base of one of the slopes by the hoist H. Then suiiicient air is released from cylinder 2| to allow the shoe 26-to rest on the ground. Compressed air is then introduced into starting the tamping action` and, at the same time, the hoist H is operated to cause the car-4 yriage slowly to ascend the slope, the continuous reciprocation of -the ram tamping a strip of earth the length of the shoe 26. Upon reaching the top of the slope, the hammer and shoe are raised to clear the earth and the hoist reversed so that the carriage returns to vthe base of the slope. The hammer is then loweredand set in operation as before and the carriage drawn across the bot- '1B tom of the ditch and up the other slope. When this strip of earth has been thus' compacted 'the entire apparatus is moved ahead the length of the tamping shoe by the winch J and the operation previously described repeated. x

Thus far we have shown our earth tampin device as adapted to being used for compacting the earth in a canal excavation. However, in a slightly modified form our invention may also be applied to tamping an embankment such as that of a reservoir or earth ll dam. Such a modification is illustrated in Fig. '7. The frame M, consisting of a pair of spaced parallel trussesv or other rigid beams, is supported` at each end on a pair of tandem wheels N rolling on single rails laid at the top and bottom of the embankment substantially as shown. Channel members O and P similar to the members D and E of Fig. 1 guide and .support the carriage F which is identical to that heretofore described with reference to Fig. I, except that only a single hoisting line Q is required and this is wound or unwound on the drum of the compressed air hoist R. Compressed air is supplied to the several devices by the comp pressor G and the winch J pulls the traveling frame ahead as before. The -flexible hoses 54 and 55 conveying air under pressure to the hammer I6 and cylinder 2|, respectively, are supported in thisv embodiment by grooved wheels 56 carried on an arm 51 pivotally mounted as at 58 on a suitable xed post, a connecting tension spring 59 keeping the hoses reasonably taut and clear of the moving carriage F.

Various modifications in the construction of the supporting truss framework and also in construction of the carriage carrying the compacting hammer and shoe may be made Without departing from the principle of our invention. It is not our intention to limit our invention lotherwise than as set forth in the claims forming part of this application.

We claim: I

1. In an earth tamping device for use on a concave ditch surface, a frame extending transversely across said surface, a track supported by said frame, said track following the contour of said surface and held by said frame spaced a uniform distance above said surface, a carriage movable in said track across said surface, means preventing the lifting of said carriage from said track, earth tamping means supported by said carriage at all times, a guide frame on said carriage perpendicular to the plane of travel of said carriage, said tamping means disposed in.said guide frame, a tamping shoe carried by said tamping means, means on said carriage for adjusting the position of said tamping means in said guide frame with respect to said surface, means located apart from said carriage for actuating said position adjusting means and for actuating said tamping means.

2. The combination described by claim 1 including springs holding said shoe in place against the bottom of said tamping means.

-3. In an earth tamping device for use on a concave ditch surface, a frame extending transversely across said surface, a track supported by said frame, said trackfollowing the contour of said surface and held by said frame spaced a uniform distance above said surface, a carriage movable in said track across said surface, said track having top guides to prevent the lifting of said carriage from said track, earth tamping means supported by said carriage at all times, a guide frame on said carriage perpendicular to the plane of travel of said carriage, said tamping means reciprocably disposed in said guide frame, a tamping shoe at the bottom of said tamping means, springs holding said shoe in place against the bottom of said tamping means, means located 5 apart from said carriage and supported on said track-suppporting frame for actuating said tamping means.

4. In an earth tamping device for use on a concave ditch surface, a frame extending trans- 1g verselyvacross said surface, a track supported by said frame, said track following the contour of said surface and held by said frame spaced a` uniform distance above said surface, a carriage movable in said track across said surface, means preventing the lifting of said carriage from said track, earth tamping means supported bysaid carriage at all times, said tamping means including a guide frame perpendicular to the plane of travel of said carriage, a compressed air hammer vslidably disposed in said guide frame, a doubleacting ram in said hammer, a tamping shoe carried by said hammer adapted to receive blows from said ram, means on said carriage for adjusting the position of said hammer with respect to said surface, means located apart from said carriage for actuating said position adjusting means and for actuating said ram.

5. The combination described by claim 4 including springs holding said shoe in place against the bottom of said hammer.

6. In an earth tamping device for use on a sloping embankment, a framev extending transversely across said surface, a track supported by said frame, said track held by said frame spaced a uniform distanceabove said surface, a carriage movable in said track, earth tamping means supported by said carriage at all times, a guide frame on said carriage perpendicular to the plane of travel of said carriage, said tamping means disposed in said guide frame, a tamping shoe carried by said tamping means, springsholding said shoe in place against the bottom of said tamping means, means carried by and operable from said track-supporting frame for operating said tamping means, means carried by and operable from said track-supporting frame for lifting said tamping means out of contact with said surface, and means on said .track-supporting frame for moving said carriage in said track.

7. In an apparatus for progressively condensing the surface material of a sharply-inclined earthwork slope such as a wall of a dug canal, a travelling'frame of girder-like form provided with an integral trackway and with means for bodily supporting and shifting said frame along said earthwork slope with said integral trackway transversely overlying the slope surface in correspondingly sharply-inclined parallelism thereto, a carriage movable up and down said inclined transverse trackway, a reciprocating ram mounted on said carriage, a tamping shoe associated with said ram for driving thereby into impacting contact With an underlying portion of the slope surface, means for directly coupling saidk carriage to said inclined trackway and preventing appreciable lifting or canting of said carriage relative thereto regardless of the degree of in-. clination in said trackway` or the amount of reaction developed by said ram during tamping operation, and means for progressively moving said carriage and its mounted ram and tamping shoe along the length of said inclined trackway as impaction of the overlain slope surface is effected by said tamping shoe, said last mentioned 'means comprising a prime mover directly supported upon the' frame proper remote from said carriage', a cable take-up and pay-out mechanism directly mounted upon said frame proper remote from said carriage and actuated by said prime mover, and a flexible cable coupled to said .carriage and extending to said take-up and-payout -mechanism :for transmitting progressive movement to said carriage as slopeimpactionw proceeds. i

. JOHN A. MCDOUGALL.

ROBERT- E. MOQARY. 

